Electronic Theses and Dissertations





Document Type


Degree Name

Doctor of Philosophy


Comm Sciences and Disorders

Committee Chair

David Kimbrough Ollerq

Committee Member

Eugene H Buder

Committee Member

Stan Franklin

Committee Member

Corrina Ethington


By analyzing infant volubility we may illuminate early communication development and aid early identification of disorders. LENA recordings provide a naturalistic method for gathering data all-day and yield automated labeling of speakers including the infant wearing the device. In Study 1, 10 six-month-old infants were studied for volubility in a naturalistic setting analyzed by LENA and a human coder using a traditional repeat-listening method based on a single all-day recording for each infant. Twelve randomly selected 5-minute segments (excluding presumed sleep) were coded for vocal type (vocants, squeals, and growls). This allowed for estimation of six-month-old infant vocal rate across an entire day, as well as rate of each vocal type in naturalistic settings and comparison between human coders and the LENA automated software analyses. These are the first human infant volubility data based on truly naturalistic sampling. This data will lay groundwork for comparing vocal rate in humanity and other species. Additionally, we may shed light on the role of volubility and the diversity of vocal types in human infancy in predicting development and disorders of language.In Study 2, twenty-four randomly sampled 5-minute segments from the same recordings as Study 1 were coded in real-time to determine effects of circumstance on volubility. Additionally, 10 five-minute segments with highest child vocalization rate (determined by LENA) and random sampling of ten presumed sleep segments (very low volubility determined by LENA) were also coded. First, coders listened to segments, coding vocalizations in real time as vocants, growls, squeals, laugh, or cry. Each coder then coded circumstance (including but not limited to vocalizations directed to the infant, vocalizations directed to others, infant alone, and infant asleep) by answering a set of questions with a scaled response. This is the first reported naturalistic assessment of infant volubility across circumstances. The work will help determine the extent to which infants use both protophones and fixed signals (cry and laugh) spontaneously, instrumentally, and in social circumstances, offering perspective on both the endogenous tendencies for vocalization in human infants and tendencies for vocalization used for communicative purposes.


Data is provided by the student.

Library Comment

Dissertation or thesis originally submitted to the local University of Memphis Electronic Theses & dissertation (ETD) Repository.